Average value for last 3 months returns incorrect average

Hi TheBaz_57 ，

In order to give you a suitable solution as soon as possible, could you please share some sample data and field settings for your matrix visual? If any measure or calculated column are referenced, please provide their formulas along with them.

Alternatively, you can refer to the following link to try to solve your problem.

Rolling 12 Months Average in DAX

CALCULATIONITEM 'PriceToUse'[Moving Average]."Rolling Avg 3M" =
    VAR NumOfMonths = 3
    VAR LastCurrentDate =
        MAX ( 'Date'[Date] )
    VAR Period =
        DATESINPERIOD ( 'Date'[Date], LastCurrentDate, - NumOfMonths, MONTH )
    VAR Result =
        CALCULATE (
            AVERAGEX (
                VALUES ( 'Date'[Calendar Year Month] ),
                SELECTEDMEASURE ()
            ),
            Period
        )
    VAR FirstDateInPeriod = MINX ( Period, 'Date'[Date] )
    VAR LastDateWithSales = MAX ( Sales[Order Date] )
    RETURN
        IF ( FirstDateInPeriod <= LastDateWithSales, Result )

Rolling Averages In Power BI

Incorrect total values fix methods:

Why Your Total Is Incorrect In Power BI - The Key DAX Concept To Understand

Dax for Power BI: Fixing Incorrect Measure Totals

Best Regards